U.S. patent application number 13/378992 was filed with the patent office on 2012-04-19 for method of scanning neighbor base station in a broadband wireless access system.
This patent application is currently assigned to LG ELECTRONICS INC.. Invention is credited to In Uk Jung, Yong Ho Kim, Jin Sam Kwak, Ki Seon Ryu.
Application Number | 20120094664 13/378992 |
Document ID | / |
Family ID | 43356930 |
Filed Date | 2012-04-19 |
United States Patent
Application |
20120094664 |
Kind Code |
A1 |
Jung; In Uk ; et
al. |
April 19, 2012 |
METHOD OF SCANNING NEIGHBOR BASE STATION IN A BROADBAND WIRELESS
ACCESS SYSTEM
Abstract
The present invention relates to a broadband wireless access
system, and more particularly, to a method for a mobile station to
efficiently scan a neighbor base station and apparatus therefor.
According to one embodiment of the present invention, in a
broadband wireless access system, a method of performing a scan,
which is performed by a mobile station to scan a neighbor base
station, includes the steps of receiving a scan response
(AAI_SCN-RSP) message including a first interval information
indicating an interval for the mobile station to receive a preamble
of the neighbor base station from a serving base station and
receiving the preamble from the neighbor base station in the first
interval. Preferably, the first interval is set by a subframe
unit.
Inventors: |
Jung; In Uk; (Gyeonggi-do,
KR) ; Kwak; Jin Sam; (Gyeonggi-do, KR) ; Kim;
Yong Ho; (Gyeonggi-do, KR) ; Ryu; Ki Seon;
(Gyeonggi-do, KR) |
Assignee: |
LG ELECTRONICS INC.
Seoul
KR
|
Family ID: |
43356930 |
Appl. No.: |
13/378992 |
Filed: |
June 17, 2010 |
PCT Filed: |
June 17, 2010 |
PCT NO: |
PCT/KR2010/003918 |
371 Date: |
December 16, 2011 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61218050 |
Jun 17, 2009 |
|
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Current U.S.
Class: |
455/434 |
Current CPC
Class: |
H04W 48/16 20130101;
H04W 24/00 20130101 |
Class at
Publication: |
455/434 |
International
Class: |
H04W 48/20 20090101
H04W048/20 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 19, 2010 |
KR |
10-2010-0024653 |
Claims
1. A method of scanning a neighbor base station by a mobile station
in a broadband wireless access system, the method comprising:
receiving a scan response (AAI_SCN-RSP) message including a first
interval information indicating an interval for the mobile station
to receive a preamble of the neighbor base station from a serving
base station; and receiving the preamble from the neighbor base
station in the first interval, wherein the first interval is set in
units of a subframe.
2. The method of claim 1, wherein the scan response message further
includes a start frame information and wherein the reception of the
preamble is performed in a frame indicated by the start frame
information.
3. The method of claim 1, wherein the scan response message
includes a first duration information and a second interval
information indicating an interval for the mobile station to
perform a data exchange with the serving base station, wherein the
first duration includes at least one second duration, and wherein
the at least one second duration includes the first interval and
base station (BS) switching times respectively located before and
after the first interval.
4. The method of claim 3, further comprising performing the data
exchange with the serving base station during a third interval
resulting from excluding the at least one second duration from the
first duration.
5. The method of claim 3, wherein the scan response message further
includes information indicating a count of iterating the first
duration and the second interval.
6. The method of claim 3, further comprising sending a scan request
message including BS switching capability information of the mobile
station for determining the base station switching time to the
serving base station.
7. The method of claim 4, wherein the first interval is a scanning
interval, wherein the second interval is an interleaving interval,
wherein the third interval is a sub-interleaving interval, wherein
the first duration is a scan duration, and wherein the second
duration is a sub-scan duration.
8. A method for supporting a mobile station to scan a neighbor base
station of a serving base station in a broadband wireless access
system, the method comprising: transmitting a scan response
(AAI_SCN-RSP) message including a first interval information
indicating an interval for the mobile station to receive a preamble
of the neighbor base station to the mobile station, wherein the
serving base station does not perform a scheduling for the mobile
station during the first interval and base station (BS) switching
times respectively located before and after the first interval.
9. The method of claim 8, wherein the scan response message
includes a first duration information and a second interval
information indicating an interval for the mobile station to
perform a data exchange with the serving base station, wherein the
first duration includes at least one second duration, and wherein
the at least one second duration includes the first interval and
the base station (BS) switching times respectively located before
and after the first interval.
10. The method of claim 9, wherein the base station performs the
scheduling on the mobile station during a third interval resulting
from excluding the at least one second duration from the first
duration.
11. The method of claim 9, wherein the scan response message
further includes information indicating a count of iterating the
first duration and the second interval.
12. The method of claim 9, further comprising receiving a scan
request message including BS switching capability information of
the mobile station for determining the base station switching time
from the mobile station.
13. The method of claim 10, wherein the first interval is a
scanning interval, wherein the second interval is an interleaving
interval, wherein the third interval is a sub-interleaving
interval, wherein the first duration is a scan duration, and
wherein the second duration is a sub-scan duration.
14. A mobile station comprising: a processor; and a radio
communication (RF) module configured to transceive a radio signal
externally under the control of the processor, wherein the
processor controls a scan to be performed by obtaining a first
interval information indicating an interval for the mobile station
to receive a preamble of the neighbor base station from a scan
response (AAI_SCN-RSP) message received from a serving base station
and then receiving the preamble from the neighbor base station in
the first interval.
15. The mobile station of claim 14, wherein the scan response
message further includes a start frame information and wherein the
processor controls the preamble to be received in a frame indicated
by the start frame information.
16. The mobile station of claim 14, wherein the scan response
message includes a first duration information and a second interval
information indicating an interval for the mobile station to
perform a data exchange with the serving base station, wherein the
first duration includes at least one second duration, and wherein
the at least one second duration includes the first interval and
base station (BS) switching times respectively located before and
after the first interval.
17. The mobile terminal of claim 16, wherein the processor controls
a data exchange with the serving base station to be performed
during a third interval resulting from excluding the at least one
second duration from the first duration.
18. The mobile terminal of claim 17, wherein the first interval is
a scanning interval, wherein the second interval is an interleaving
interval, wherein the third interval is a sub-interleaving
interval, wherein the first duration is a scan duration, and
wherein the second duration is a sub-scan duration.
Description
TECHNICAL FIELD
[0001] The present invention relates to a broadband wireless access
system, and more particularly, to a method for a mobile station to
efficiently scan a neighbor base station and apparatus
therefor.
BACKGROUND ART
[0002] First of all, in the following description, a method for a
mobile station to perform scanning on a neighbor base station is
explained.
[0003] FIG. 1 is a flowchart for a method of scanning a neighbor
base station according to a related art.
[0004] Referring to FIG. 1, a serving base station connected to a
mobile station broadcasts information on a neighbor base station to
all mobile stations within its cell.
[0005] The information on the neighbor base station is carried on a
neighbor advertisement (MOB_NBR-ADV) message. Table 1 shows one
example for a configuration of MOB_NBR-ADV message.
TABLE-US-00001 TABLE 1 Syntax Size Notes
MOB_NBR-ADV_Message_Format( ){ Management Message Type=49 8 bits
Operator ID 24 bits Unique ID assigned to the operator N_NEIGHBORS
8 bits For(j=0; j<N_NEIGHBORS; j++){ Neighbor BS-ID 48 bits
Physical Frequency 32 bits Configuration Change Count 8 bits
Hysteresis threshold 8 bits MAHO report period 8 bits TVL Encoded
Neighbor information Variable TLV specific } }
[0006] Referring to Table 1, the number of neighbor base stations,
a neighbor base station identifier (BSID), frequency used by a
neighbor base station, channel information of a neighbor base
station and the like are included in the MOB_NBR-ADV message.
[0007] Having received this message, the mobile station temporarily
stops receiving the data transmitted by the serving base station
and then sends a scan request (MOB_SCN-REQ) message for obtaining a
duration for channel quality measurement from the neighbor base
station to the serving base station. Table 2 shows one example for
a configuration of MOB_SCN-REQ message.
TABLE-US-00002 TABLE 2 Syntax Size Notes
MOB_SCN_REQ_Message_Format( ){ Management Message Type = 50 8 bits
Scan Duration 12 bits Units are frames Reserved 4 bits }
[0008] While the mobile station is measuring a channel quality of
the neighbor base station, the serving base station stops
transmitting data to the mobile station. Afterwards, the serving
base station is then able to transmit data after the scan duration
requested by the mobile station. The serving base station sends a
scan response (MOB_SCN-RSP) message to the mobile station in
response to the MOB_SCN-REQ. Table 3 shows one example for a
configuration of MBO_SCN-RSP message.
TABLE-US-00003 TABLE 3 Syntax Size Notes
MOB_SCN-RSP_Message_Format( ){ Management Message Type = 50 8 bits
Scan Duration 12 bits Units are frames Start Frame 4 bits }
[0009] Referring to Table 3, the base station secures the scan
duration requested by the mobile station. Subsequently, the mobile
station waits for a time of a start frame and then starts a base
station scan.
[0010] For the scan duration, the mobile station receives a
preamble of the neighbor base station. Before describing the
preamble, a frame structure of IEEE 802.16m system is explained as
follows.
[0011] First of all, a frame structure of a system, which meets the
IEEE 802.16m specification, is configured by a unit of super frame
(SFH). Each SFH is transmitted by 20 ms periodicity. One SFH
consists of 6, 7 or 8 subframes. Various subframe types and sizes
are defined for the SFH according to at least one of a system
bandwidth, a cyclic prefix (CP) length and the like. In case of
type-1, a subframe length is 0.617 ms. A pattern, at which an
uplink/downlink (UL/DL) map for data transmission and reception is
located, is indicated by the SFH. In this case, the uplink/downlink
(UL/DL) map can be received in each subframe time or each second
subframe (i.e., one MP for 2 subframes).
[0012] In general, a preamble is transmitted by a frame unit from a
base station. And, preambles can be classified into a PA preamble
and an SA preamble. In this case, the PA preamble is a primary
advanced preamble. And, information on a system bandwidth and
carrier setting can be included in the PA preamble. Meanwhile, the
SA preamble is a secondary advanced preamble. Information on a cell
ID, a base station type and the like can be included in the SA
preamble. And, the SA preamble is required for obtaining basic
synchronization. In this case, the base station type can include
such information as a macro base station, a femto base station and
the like.
[0013] One super frame generally carries one PA preamble and three
SA preambles. A most efficient preamble transmission sequence for a
scan includes [SA Preamble], [PA Preamble], [SA Preamble] and [SA
Preamble] in order.
[0014] When a mobile station scans a neighbor base station
operating on an inter-frequency different from that of a serving
base station, an interruption time occurs in the course of a
communication with the serving base station. This is attributed to
the fact that the mobile station receives a preamble of the
neighbor base station and then temporarily interrupts the
communication with the serving base station to match
synchronization in downlink (DL). This is explained with reference
to FIG. 2 as follows.
[0015] FIG. 2 is a diagram for an interruption time that may occur
in the course of performing a scan in a general IEEE 802.16e
network.
[0016] Referring to FIG. 2, a mobile station sends a scan request
message to a serving base station to attempt a scan of a neighbor
base station in the course of performing data exchange with the
serving base station. In response to the scan request message,
having received the scan request message, the mobile station
performs a scan of the neighbor base station during a scan
length/interval (scan duration/interval) by a frame unit from a
timing point indicated by start frame (start_frame) information
included in the received message.
[0017] Total interruption time occurring due to the scan is 10 ms.
That is, the interruption time starts when a base station (BS)
switching starts with a third frame. And, the interruption time
ends before a start of a next frame after the reception of the
preamble of the neighbor base station. Hence, total 10 ms
interruption time occurs. In this case, the base station (BS)
switching time is variable but is assumed as 1 subframe.
[0018] In doing so, although the information necessary for the
mobile station is one preamble only, 10 ms is consumed to receive
it normally. Therefore, a scan procedure for reducing the
unnecessarily occurring interruption time is requested. In
addition, in case of the general IEEE 802.16e (WiMAX Rel 1.0 or
Rel. 1.5), as scan information can be obtained from one preamble
transmitted each frame of 5 ms length, even if a scan interval is
set for a random frame, it is able to obtain preamble information
of the neighbor base station. However, in case of the IEEE 802.16m
system, when additional time synchronization is necessary for
inter-frequency due to a sync channel divided into a primary sync
channel and a secondary sync channel, acquisition of the primary
sync channel is requested or acquisition of the secondary sync
channel is necessary for a cell ID based scan. Thus, when the
hierarchical sync channel structure is taken into consideration, an
efficient scheme for a scan interval setting and indication of the
scan interval setting is requested.
DISCLOSURE OF INVENTION
Technical Problem
[0019] Accordingly, the present invention is directed to a method
for a mobile station to efficiently scan a neighbor base station
and apparatus therefore that substantially obviate one or more of
the problems due to limitations and disadvantages of the related
art.
[0020] An object of the present invention is to provide a scanning
method and apparatus, by which a scan can be efficiently performed
in a manner of reducing an interruption time attributed to the
scan.
[0021] Another object of the present invention is to provide a
scanning method and apparatus, by which a scan can be efficiently
performed in consideration of a base station switching capability
of a mobile station.
[0022] Additional features and advantages of the invention will be
set forth in the description which follows, and in part will be
apparent from the description, or may be learned by practice of the
invention. The objectives and other advantages of the invention
will be realized and attained by the structure particularly pointed
out in the written description and claims thereof as well as the
appended drawings.
Solution to Problem
[0023] The present invention discloses an efficient neighbor base
station scanning method to solve the above technical tasks.
[0024] To achieve these and other advantages and in accordance with
the purpose of the present invention, as embodied and broadly
described, in a broadband wireless access system, a method of
performing a scan, which is performed by a mobile station to scan a
neighbor base station, includes the steps of receiving a scan
response (AAI_SCN-RSP) message including a first interval
information indicating an interval for the mobile station to
receive a preamble of the neighbor base station from a serving base
station and receiving the preamble from the neighbor base station
in the first interval, wherein the first interval is set by a
subframe unit.
[0025] Preferably, the scan response message further includes start
frame information and the preamble receiving step is performed in a
frame indicated by the start frame information.
[0026] Preferably, the scan response message includes a first
duration information and a second interval information indicating
an interval for the mobile station to perform a data exchange with
the serving base station, the first duration includes at least one
second duration, and the at least one second duration includes the
first interval and base station (BS) switching times respectively
located before and after the first interval.
[0027] More preferably, the method further includes the step of
performing the data exchange with the serving base station during a
third interval resulting from excluding the at least one second
duration from the first duration.
[0028] More preferably, the scan response message further includes
information indicating a count of iterating the first duration and
the second interval.
[0029] More preferably, the method further includes the step of
sending a scan request message including BS switching capability
information of the mobile station for determining the base station
switching time to the serving base station.
[0030] More preferably, the first interval is a scanning interval,
the second interval is an interleaving interval, the third interval
is a sub-interleaving interval, the first duration is a scan
duration, and the second duration is a sub-scan duration.
[0031] To further achieve these and other advantages and in
accordance with the purpose of the present invention, in a
broadband wireless access system, a method of supporting a scan,
which is supported by a serving base station to enable a mobile
station to scan a neighbor base station, includes the step of
sending a scan response (AAI_SCN-RSP) message including a first
interval information indicating an interval for the mobile station
to receive a preamble of the neighbor base station to the mobile
station, wherein the serving base station does not perform a
scheduling of the mobile station during the first interval and base
station (BS) switching times respectively located before and after
the first interval.
[0032] Preferably, the scan response message includes a first
duration information and a second interval information indicating
an interval for the mobile station to perform a data exchange with
the serving base station, the first duration includes at least one
second duration, and the at least one second duration includes the
first interval and the base station (BS) switching times
respectively located before and after the first interval.
[0033] More preferably, the base station performs the scheduling on
the mobile station during a third interval resulting from excluding
the at least one second duration from the first duration.
[0034] More preferably, the scan response message further includes
information indicating a count of iterating the first duration and
the second interval.
[0035] More preferably, the method further includes the step of
receiving a scan request message including BS switching capability
information of the mobile station for determining the base station
switching time from the mobile station.
[0036] More preferably, the first interval is a scanning interval,
the second interval is an interleaving interval, the third interval
is a sub-interleaving interval, the first duration is a scan
duration, and the second duration is a sub-scan duration.
[0037] To further achieve these and other advantages and in
accordance with the purpose of the present invention, a mobile
station includes a processor and a radio communication (RF) module
configured to transceive a radio signal externally under the
control of the processor, wherein the processor controls a scan to
be performed by obtaining a first interval information indicating
an interval for the mobile station to receive a preamble of the
neighbor base station from a scan response (AAI_SCN-RSP) message
received from a serving base station and then receiving the
preamble from the neighbor base station in the first interval.
[0038] Preferably, the scan response message further includes a
start frame information and the processor controls the preamble to
be received in a frame indicated by the start frame
information.
[0039] More preferably, the scan response message includes a first
duration information and a second interval information indicating
an interval for the mobile station to perform a data exchange with
the serving base station, the first duration includes at least one
second duration, and the at least one second duration includes the
first interval and base station (BS) switching times respectively
located before and after the first interval.
[0040] In this case, the processor controls a data exchange with
the serving base station to be performed during a third interval
resulting from excluding the at least one second duration from the
first duration.
[0041] Moreover, the first interval is a scanning interval, the
second interval is an interleaving interval, the third interval is
a sub-interleaving interval, the first duration is a scan duration,
and the second duration is a sub-scan duration.
[0042] It is to be understood that both the foregoing general
description and the following detailed description are exemplary
and explanatory and are intended to provide further explanation of
the invention as claimed.
Advantageous Effects of Invention
[0043] Accordingly, the present invention provides the following
effects or advantages.
[0044] First of all, using embodiments of the present invention, as
a scanning interval is allocated by a subframe unit, an
interruption time due to a scan is reduced. Therefore, a scanning
operation of a mobile station can be efficiently performed.
[0045] Secondly, using embodiments of the present invention, a base
station switching capability of a mobile station is negotiated
through a scan request message and a scan response message, whereby
a scan can be performed more efficiently.
BRIEF DESCRIPTION OF DRAWINGS
[0046] The accompanying drawings, which are included to provide a
further understanding of the invention and are incorporated in and
constitute a part of this specification, illustrate embodiments of
the invention and together with the description serve to explain
the principles of the invention.
[0047] In the drawings:
[0048] FIG. 1 is a flowchart for a method of scanning a neighbor
base station according to a related art;
[0049] FIG. 2 is a diagram for an interruption time that may occur
in the course of performing a scan in a general IEEE 802.16e
network;
[0050] FIG. 3 is a diagram of one example for a scan performing
procedure according to one embodiment of the present invention;
[0051] FIG. 4 is a diagram of one example for a scan duration and
interleaving interval setting according to another embodiment of
the present invention;
[0052] FIG. 5 is a diagram of a relation between start frame
information and base station switching time according to another
embodiment of the present invention; and
[0053] FIG. 6 is a block diagram of one example for a transmitting
and receiving side structure according to another embodiment of the
present invention.
MODE FOR THE INVENTION
[0054] The present invention relates to a wireless access system.
Reference will now be made in detail to methods of efficient
neighbor base station scan according to various embodiments of the
present invention, examples of which are illustrated in the
accompanying drawings.
[0055] First of all, the following embodiments correspond to
combinations of elements and features of the present invention in
prescribed forms. And, it is able to consider that the respective
elements or features are selective unless they are explicitly
mentioned. Each of the elements or features can be implemented in a
form failing to be combined with other elements or features.
Moreover, it is able to implement an embodiment of the present
invention by combining elements and/or features together in part. A
sequence of operations explained for each embodiment of the present
invention can be modified. Some configurations or features of one
embodiment can be included in another embodiment or can be
substituted for corresponding configurations or features of another
embodiment.
[0056] In the description of the drawings, procedures, steps and/or
the like are not described to avoid making the gist of the present
invention unclear.
[0057] In this disclosure, embodiments of the present invention are
described centering on the data transmission/reception relations
between a base station and a mobile station. In this case, the base
station is meaningful as a terminal node of a network which
directly performs communication with the terminal. In this
disclosure, a specific operation explained as performed by a base
station can be performed by an upper node of the base station in
some cases.
[0058] In particular, in a network constructed with a plurality of
network nodes including a base station, it is apparent that various
operations performed for communication with a mobile station can be
performed by a base station or other networks except the base
station. In this case, `base station` can be replaced by such a
terminology as a fixed station, a Node B, an eNode B (eNB), an
advanced base station (ABS), an access point and the like. And,
`mobile station` can be replaced by such a terminology as a user
equipment (UE), a subscriber station (SS), a mobile subscriber
station (MSS), a mobile terminal, an advanced mobile station (AMS)
and the like.
[0059] Moreover, a transmitting side means a node configured to
transmit a data or speech service and a receiving side means a node
configured to receive the data or speech service. Therefore, in
uplink, a mobile station becomes a transmitting side and a base
station can become a receiving side. On the contrary, in downlink,
a mobile station becomes a receiving side and a base station can
become a transmitting side.
[0060] Besides, a mobile station of the present invention can
include a PDA (personal digital assistant), a cellular phone, a PCS
(personal communication service) phone, a GSM (global system for
mobile) phone, a WCDMA (wideband CDMA) phone, an MBS (mobile
broadband system) phone or the like.
[0061] Embodiments of the present invention can be implemented
using various means. For instance, embodiments of the present
invention can be implemented using hardware, firmware, software
and/or any combinations thereof.
[0062] In the implementation by hardware, a method according to
each embodiment of the present invention can be implemented by at
least one selected from the group consisting of ASICs (application
specific integrated circuits), DSPs (digital signal processors),
DSPDs (digital signal processing devices), PLDs (programmable logic
devices), FPGAs (field programmable gate arrays), processor,
controller, microcontroller, microprocessor and the like.
[0063] In case of the implementation by firmware or software, a
method according to each embodiment of the present invention can be
implemented by modules, procedures, and/or functions for performing
the above-explained functions or operations. Software code is
stored in a memory unit and is then drivable by a processor. The
memory unit is provided within or outside the processor to exchange
data with the processor through the various well-known means.
[0064] Embodiments of the present invention are supportable by
standard documents disclosed in at least one of wireless access
systems including IEEE 802 system, 3GPP system, 3GPP LTE system and
3GPP2 system. In particular, the steps or parts, which are not
explained to clearly reveal the technical idea of the present
invention, in the embodiments of the present invention can be
supported by the above documents. Moreover, all terminologies
disclosed in this document can be supported by at least one of
P802.16-2004, P802.16e-2005, P802.16Rev2 and P802.16m documents
which are the standards of IEEE 802.16 system.
[0065] Specific terminologies used in the following description are
provided to help the understanding of the present invention. And,
the use of the specific terminology can be modified into another
form within the scope of the technical idea of the present
invention.
First Embodiment
[0066] According to one embodiment of the present invention, in
order to enable a scan of a neighbor base station by reducing an
interruption time, it is proposed to set a scanning interval not by
a frame unit but by a subframe unit.
[0067] For this, it is able to allocate a scanning interval of a
mobile station so that the scanning interval can match a specific
one of preambles of neighbor base stations (e.g., an SA
preamble).
[0068] That is, in case of performing a scan procedure on the
assumption that a base station has a frame structure of a general
IEEE 802.16m system, a scanning interval enough to receive one
preamble from a scanning target base station can be allocated to a
mobile station. This is explained with reference to FIG. 3 as
follows.
[0069] FIG. 3 is a diagram of one example for a scan procedure
according to one embodiment of the present invention.
[0070] In FIG. 3, it is assumed that a base station (BS) switching
time of a mobile station is set to 1 subframe.
[0071] Referring to FIG. 3, while a mobile station is performing a
data exchange with a serving base station [S301], the mobile
station sends a scan request (AAI_SCN-REQ) message to the serving
station to scan a neighbor base station [S302].
[0072] In response to the scan request made by the mobile station,
the serving base station sends a scan response (AAI_SCN-RSP)
message to the mobile station [S303]. In this case, start frame
information, start offset information, scanning interval
information of a subframe unit and the like can be included in the
scan response message.
[0073] If the start frame information included in the scan response
message indicates a 4th frame, since a base station switching time
is 1 subframe, the mobile station performs a base station switching
in an 8th subframe of a 3rd frame, receives an SA preamble of the
4th frame corresponding to a scanning interval, and then performs a
switching to the serving station in a next subframe again
[S304].
[0074] Afterwards, the mobile station receives a DL map of the
serving base station and is then able to normally perform a data
exchange with the serving base station.
[0075] As mentioned in the description of the above method, an
interruption time generated from allocating a scanning interval at
a subframe level amounts to 3 subframes, i.e., 1.851 ms. Compared
to a general scanning method, this indicates that the interruption
time can be reduced by 8.149 ms (i.e., 81.5%). In case of a
subframe in which an SA preamble is transmitted, since a mobile
station is able to perform camping within a corresponding subframe
after detection of the SA-preamble of one symbol, a substantial
interruption time can be reduced up to 2 subframes. Moreover, as a
reception-transmission gap (RTG) for current time division duplex
(TDD) or an idle time for frequency division duplex (FDD) is
defined at a last part of a UL subframe, if inter-frequency camping
is performed using the RTG or the idle time, a scan can be
performed within one subframe extremely. That is, a substantial
scanning interval can includes minimum 1 subframe up to maximum
plural subframes. Therefore, whether a base station allocates a
scanning interval of a prescribed value to a mobile station can be
determined according to: 1) BS switching capability of a mobile
station; or 2) frequency assignment (FA) of a switching target base
station (e.g., a scan target base station).
[0076] 1) BS switching time according to capability of a mobile
station
[0077] On the assumption that each mobile station can have a
different base station (BS) switching time, a mobile station
informs a base station of its BS switching time via capability
negotiation in an initial network access (i.e., capability
negotiation via AAI_SBC-REQ and AAI_SBC-RSP messages) or a scan
request message sent to the base station during a scanning
procedure. If the base station enables a scan to be performed via a
scan response message while unaware of the BS switching time
capability of the mobile station, the base station is able to
allocate a scanning interval via a scan response message in
consideration of a BS switching time that can be set to a greatest
value.
[0078] 2) BS switching time according to frequency assignment (FA)
of a switching target base station
[0079] As IEEE 802.16m system considers a multi-carrier
configuration, each base station is able to exchange information
via a plurality of frequency assignments (FA). Therefore,
inter-frequency scanning or inter-frequency handover (HO) can occur
frequently. Thus, if a frequency assignment (FA), on which a scan
target base station operates, currently has a big difference from a
frequency assignment of a serving base station, a BS switching time
may increase. On the contrary, if a frequency assignment of a scan
target base station is contiguous with that of a serving base
station, a BS switching time of a mobile station will decrease to
the extent of the contiguousness. Therefore, the serving base
station is able to allocate a scanning interval to the mobile
station in consideration of the frequency assignment of the scan
target base station.
[0080] Meanwhile, when a base station allocates a scanning interval
of a subframe unit to a mobile station via AAI_SCN-RSP message,
interleaving interval information can be delivered to the mobile
station as well. In this case, the interleaving interval means an
interval configured to enable a mobile station to perform a data
exchange with a serving base station because a scan is not
scheduled between scanning intervals.
[0081] In the following description, one example for a scan
response (AAI_SCN-RSP) message containing the above mentioned
informations is explained with reference to Table 4.
TABLE-US-00004 TABLE 4 Syntax Size (bit) Notes
AAI_SCN-RSP_Message_format( ) { Management Message Type = 8 x5
Report mode 2 0b00: No report 0b01: Periodic report 0b10:
Event-triggered report 0b11: One-time scan report Reserved 3
Rsp_Seq_Num 1 One-bit sequence number for this message that is
toggled for each new message. Use_Nbr_Bitmap_Index 1 Indicates if
the bitmap of BS indexes for AAI_NBR-ADV is used. 0: Bitmap of BS
indexes for AAI_NBR-ADV is not used. 1: Bitmap of BS indexes for
AAI_NBR-ADV is not used. Use_Req_Bitmap_Index 1 Indicates if the
bitmap of BS indexes for AAI_SCN-REQ is used. 0: Bitmap of BS
indexes for AAI_SCN-REQ is not used. 1: Bitmap of BS indexes for
AAI_SCN-REQ is not used. Report period 8 If Report mode is set to
0b01 or 0b11, this is the Report Period, in frames; otherwise this
field is set to 0. For MS request denied (Scan Duration == 0),
Report period is the number of frames that BS suggests to MS before
transmitting next AAI_SCN-REQ. Report metric 8 Bitmap indicating
metrics on which the cor-responding triggers are based: Bit 0: BS
CINR mean Bit 1: BS RSSI mean Bit 2: RTD mean Bit 3: Number of
missed frames Bits 4-7: Reserved; shall be set to zero. if (Scan
Duration != 0) { Start frame 8 Interleaving interval 8 Duration in
frames. Scan iteration 8 If( Use_Nbr_Bitmap_Index == 1){
Configuration change count 8 for AAI_NBR-ADV Reserved 2 Shall be
set to zero Nbr_Bitmap_Size 6 Size of Nbr_Bitmap_Index in nibbles
((Nbr_Bitmap_Size + 1)*4), which may be less than or equal to the
number of BSs in AAI_NBR-ADV. Nbr_Bitmap_Index (Nbr_Bit- Each bit
position in this bitmap cor- map_Size + 1)*4 responds to a BS Index
of the corre- sponding AAI_NBRADV message, where the least
significant bit corresponds to the first BS Index, each next sig-
nificant bit corresponds to the next BS Index, the most significant
bit cor- responds to the BS Index of the last rec- ommended BS, and
BSs with BS Index greater than the last recommended BS are not
recommended and do not have a cor- responding bit position in the
bitmap. Bitmap position bit value: 0: the corre- sponding BS is not
recommended. 1: the corresponding BS is recommended. When
Use_Req_Bitmap_Index equals 1, Nbr_Bitmap_Index only includes BSs
that were included in the AAI_NBR-ADV message but that were not
included in the corresponding AAI_SCN-REQ message. For( each `1` in
Nbr_Bitmap_Index ){ Nbr_Frame_offset 3 The relative frame offset
value of the Nbr_BS in subframe units (max 8 subframes). In case
the Nbr_BS has different frame configuration to the S- ABS, the
Start frame shall take account this frame offset value for correct
frame (preamble) alignment during scanning. If this value is 0, it
implies that the Nbr_BS is well aligned with the S-ABS. If
(Nbr_Frame_offset !=0) 8 If the frame offset of the NBR_BSis
Frame_configuration_informa different from the S-ABS, the BS type
tion is different and so will be the frame configuration (mixed
mode, 16m only mode, YBS etc). This information includes the
related frame con- figuration information (details of what to
include is TBD). This may also be included as a TLV.
Scanning_interval 3 Number of subframes to scan at the Nbr_BS
Nbr_Scanning_start_frame 1 The specific starting point for scanning
within a superframe. The end point will be the scanning interval
value in addition of this value. Since the AMS has to receive the
SFH, and while the Primary-Preamble does not aid synchro- nization,
the AMS shall receive either one of the remaining 2
secondary-Preambles. If 0, it means that the first S-preamble is to
be scanned as the scanning initiating point. If 1, it means that
the second S- preamble is to be scanned as the scanning initiating
point. N_Recommended_BS_Carrier 8 Number of carriers to be scanned
for this neighbor BS. If (N_Recommended_BS_Carrier !=0) {
Recommended_BS_Carrier_B 8 Index of carrier to be scanned for this
itmap_Index neighbor BS For (j=0; j < N_Recommended_BS_Carrier;
j++){ Start_frame_offset 8 The time offset in units of frames for
each carrier index that is toggled in the Rec-
ommended_BS_Carrier_Bitmap_Index to start scanning. Each
Start_frame_offset refers to the toggled carrier index in orderly
manner. } } } } else { N_Recommended_BS_Index 8 Number of
neighboring BS to be scanned or associated, which are using BS
index that corresponds to the position of BS in AAI_NBR-ADV
message. If N_Recommended_BS_Index, N_Recommended_BS_Full,
Use_Nbr_Bitmap_Index, and Use_Req_Bitmap_Index are set to 0, the BS
recommends the MS scan all neighbors listed in the AAI_NBR-ADV
message. MS may scan a sub-set of the list.
If(N_Recommended_BS_Index !=0){ Configuration change count 8
Configuration Change Count value of for AAI_NBR-ADV referring
AAI_NBR-ADV message. } If( Use_Req_Bitmap_Index == 1) Req_Seq_Num 1
One-bit sequence number for the correspond-ing AAI_SCN-REQ message.
Reserved 1 Req_Bitmap_Size 6 Size of Req_Bitmap_Index in nibbles
((Req_Bitmap_Size + 1)*4), which may be less than or equal to the
number of BSs in AAI_SCN-REQ. Req_Bitmap_Index (Req_Bit- Each bit
position in this bitmap cor- map_Size + 1)*4 responds to a BS Index
of the corre- sponding AAI_SCNREQ message, where the least
significant bit corresponds to the first BS Index, each next
significant bit corresponds to the next BS Index, the most
significant bit corresponds to the BS Index of the last
rec-ommended BS, and BSs with BS Index greater than the last
recommended BS are not recommended and do not have a correspond-ing
bit position in the bitmap. Bitmap position bit value: 0: the
corresponding BS is not recom-mended. 1: the corresponding BS is
recommended. for( each `1` in Req_Bitmap_Index ) {
N_Recommended_BS_Carrier 8 Number of carriers to be scanned for
this neighbor BS. If (N_Recommended_BS_Carrier !=0) {
Recommended_BS_Carrier_B 8 Index of carrier to be scanned for this
itmap_Index neighbor BS For (j = 0; j <
N_Recommended_BS_Carrier; j++){ Start_frame_offset 8 The time
offset in units of frames for each carrier index that is toggled in
the Rec- ommended_BS_Carrier_Bitmap_Index to start scanning. Each
Start_frame_offset refers to the toggled carrier index in orderly
manner. } } } } N_Recommended_BS_Full 8 Number of neighboring BS to
be, which are using full 48 bits BS ID. For(j = 0; j <
N_Recommended_BS_Full; j++){ Recommended BS ID 48 BS IDs of BSs
that MS shall scan. } Padding variable } TLV encoded information
variable }
[0082] Referring to Table 4, neighbor frame offset
(Nbr_Frame_offset) information set by a subframe unit is included
in a scan response message. If a frame structure of a scan target
base station is different from that of a serving base station, it
is able to inform a mobile station of offset information to match a
timing point of transmitting a preamble from the scan target base
station.
[0083] If a neighbor frame offset is not set to 0 (i.e., if a frame
structure is different from that of a serving base station), frame
configuration information of a target base station can be further
transmitted.
[0084] And, scanning interval information set by a unit of subframe
can be included in the scan response message.
[0085] Moreover, neighbor scanning start frame
(Nbr_Scanning_start_frame) information can be included in the scan
response message. This information indicates a timing point for a
mobile station to start a scan within a super frame. The end point
of the scanning can correspond to a timing point at which a
scanning interval elapses from a point indicated by the neighbor
scanning start frame information. As a super frame header is
transmitted in a first subframe in a super frame and a PA preamble
is transmitted in a second subframe, a mobile station is able to
receive an SA preamble via a third or fourth frame. When the
neighbor scanning start frame information has a 1-bit size, if it
is set to 0, it means that a first SA preamble (e.g., 3rd frame) is
to be scanned as the scanning initiating point by a mobile station.
If it is set to 1, it means that a second SA preamble (e.g., 4th
frame) is to be scanned as the scanning initiating point by a
mobile station. Alternatively, the scanning start frame information
includes 2 bits to indicate one of four frames. Alternatively, the
scanning start frame information is configured as 4-bit bitmap to
indicate at least one frame in order.
[0086] Meanwhile, the information on the interleaving interval,
which is the interval for a mobile station to perform a data
exchange with a serving base station because a scan is not
scheduled between the scanning intervals, can be included in the
scan response message as well.
Second Embodiment
[0087] According to another embodiment of the present invention,
when a mobile station performs a scan on a neighbor base station, a
method of further reducing an interruption time by subdividing a
scan duration is provided.
[0088] In particular, a scanning operation of a mobile station can
be performed in a manner of being divided into an interleaving
interval having a scan fail to be scheduled therein and a scan
duration having a scan performed therein. In this case, the scan
duration can be subdivided into a sub-scan duration, in which a
mobile station performs a base station switching and a preamble
reception, and a sub-interleaving interval in which a mobile
station can perform a data exchange with a serving base station.
That is, since a mobile station is able to perform a communication
with a serving base station during a sub-interleaving interval
despite a scan duration, the serving base station is able to
perform a scheduling on the corresponding mobile station.
[0089] A mobile station receives an allocation of information
necessary for a scanning via a scan response message to perform a
scan. The information may include a scanning interval, a scan
duration, a start frame indicating a start frame of initial scan
duration, an interleaving interval indicating a duration or length
of an interval for performing a normal communication with a serving
base station, a scan iteration information indicating how many
times a scan duration and an interleaving interval are iterated,
and the like.
[0090] Since a time (i.e., a BS switching time) for a mobile
station to switch to a status capable of receiving a frequency of a
neighbor base station by changing a frequency of each mobile
station to perform a scan of a subframe unit differs from that of
another mobile station, the mobile station is able to send a scan
request (AAI_SCN-REQ) message to a serving base station in case of
making a scan request thereto in a manner that its BS switching
capability is included in the scan request message. In response to
the scan request message, the serving base station sends a scan
response (AAI_SCN-RSP) message including scanning interval
information to the mobile station in a manner that the scanning
interval information is set in consideration of the BS switching
capability of the mobile station.
[0091] In doing so, as mentioned in the foregoing description, if a
transition time greater than a specific interval (e.g., subframe,
symbol, idle time, RTG, etc.) is requested by the mobile station
like the case of performing a camping by utilizing an idle
time/transmission-reception transition gap (TTG) in the UL
interval, granularity predefined in the scanning interval can be
further allocated. For this, it is able to set a scanning interval
in a manner that a presence or non-presence of additional
allocation of a scanning interval is indicated via a mobile station
feedback of 1-bit indication level.
[0092] In this case, the scanning interval in the scan duration, an
interval corresponding to a BS switching time before the scanning
interval and an interval corresponding to the BS switching time
after the scanning interval can become a sub-scan duration or an
interval resulting from excluding the sub-scan duration from the
scan duration can become a sub-interleaving interval. This is
explained with reference to FIG. 4 as follows.
[0093] FIG. 4 is a diagram of one example for a scan duration and
interleaving interval setting according to another embodiment of
the present invention. In FIG. 4, assume that a base station (BS)
switching time is negotiated into 1 subframe between a mobile
station and a serving base station.
[0094] Referring to FIG. 4, in a scanning interval negotiation,
both a mobile station and a serving base station mutually recognize
that 1 subframe before a specific subframe (i.e., a subframe in
which a preamble is transmitted) of a scan target base station and
1 subframe after the specific subframe are not available.
Therefore, the serving base station is aware that the mobile
station is not available during total 3 subframe intervals (i.e.,
sub-scan duration) including a subframe, in which a preamble of the
scan target base station is transmitted, in a scanning interval and
does not perform scheduling (control signaling included) for data
allocation to the mobile station. In this case, if a camping is
performed within a subframe for transmitting a preamble, transition
(BS switching) is possible within the corresponding subframe.
Hence, the scan duration can be set to a level of 1 or 2 subframes.
Moreover, the sub-scan duration and the sub-interleaving interval
can be iterated within the scan duration. Therefore, the mobile
station is able to receive all of the SA preamble, PA preamble and
super frame header of the san target base station during one san
duration according to the settings of a start frame value and the
scan duration.
[0095] Meanwhile, according to another example of the present
embodiment, start and end points of a scan can be allocated in
consideration of a BS switching time. This is explained with
reference to FIG. 5 as follows.
[0096] FIG. 5 is a diagram of a relation between start frame
information and base station switching time according to another
embodiment of the present invention.
[0097] Referring to FIG. 5, a scan duration starts with a timing
point ahead of a BS switching time in a frame indicated by start
frame information of a frame unit. So to speak, `point indicated by
a start frame minus BS switching time` becomes a start point of an
initial san duration, i.e., a scan start timing point.
[0098] According to another example for the present embodiment, a
start frame can be allocated by a subframe unit. In this case, a
start frame value preferably indicates a start point of a scan
duration in consideration of a BS switching time.
Third Embodiment
[0099] According to a further embodiment of the present invention,
a scanning method in further consideration of a legacy system is
proposed.
[0100] Legacy system in this disclosure includes a system to which
general technologies including IEEE 802.16e (wirelessMAN-OFDMA
reference system) specification. A frame structure of a base
station of IEEE 802.16m specification supporting this legacy system
specification (wirelessMAN-OFDMA reference system/WirelessMAN OFDMA
advanced coexisting system, legacy supportive) is operated in a
manner of dividing parts of DL/UL interval into LZone (IEEE 802.16e
specification supportive) and MZone (IEEE 802.16m specification
supportive) (e.g., TDD). In this disclosure, for clarity and
convenience, a base station (ABS) mode supporting a legacy mobile
station is named `mixed mode` and a base station (ABS) mode not
supporting a legacy mobile station is named `16m only mode`.
[0101] According the present invention, scanning operations of a
mobile station, which meets the IEEE 802.16m specification, can be
classified into the followings.
[0102] (1) Case of scanning to a 16m-only neighbor base station
(NBR-ABS) from a serving base station operating in mixed mode
[0103] Since an NBR-ABS operates in 16m-only mode, a preamble is
transmitted at a start position of a DL subframe, which may differ
from a subframe for transmitting a preamble of a serving base
station MZone. Preferably, information on this is carried on
AAI_SCN-RSP message. Since a mobile station inevitably performs a
BS switching (transition) in the Mzone of a serving base station to
perform a scan to a subframe of a DL start position of a scan
target base station in case of setting a san duration, a BS
switching time should be further taken into consideration.
[0104] (2) Case of scanning to a neighbor base station operating in
mixed mode from a serving base station operating in 16m-only
mode
[0105] Since an NBR-ABS operated in a mixed mode, a position of a
subframe for transmitting a preamble varies according to a frame
offset of the NBR-ABS or LZone/Mzone setting. Therefore, the
corresponding information is preferably carried on AAI_SCN-RSP.
Moreover, a scan duration is preferably determined in consideration
of a BS switching time before or after MZone start DL subframe of a
scan target base station. For this, in case that offset information
of MZone of NBR-ABS is carried on AAI_SCN-RSP message, it is able
to set a scan duration before or after a subframe for transmitting
a preamble in a manner of combining corresponding information,
start frame information, a base station switching time and the like
together. In case that a scan target base station is a neighbor
base station not included in a neighbor advertisement (AAI_NBR-ADV)
message, a mobile station is unaware of the aforesaid frame offset
or LZone/MZone setting information, the mobile station is informed
on the corresponding information via the AAI_SCN-RSP message.
[0106] (3) Case of scanning to a neighbor base station (NBR-ABS)
operating in mixed mode from a serving base station operating in
mixed mode
[0107] If the setting of LZone/MZone of a serving base station is
equal to that of a scan target base station, a mobile station is
able to perform a scan on the san target base station without
separate information using information on a frame structure of the
serving base station. Yet, each base station can have a zone
setting different per carrier for load balancing of LZone and the
like in general.
[0108] Considering this, a mobile station needs to obtain
information on a subframe, in which a preamble is transmitted, from
MZone of an NBR-ABS. In doing so, regarding a san duration setting,
since LZone interval exists in a serving base station as well as
the NBR-ABS in case of downlink, an interval setting of a start
subframe of the MZone is not necessary. Therefore, regarding the
scan duration setting information, it is possible to turn off an
operation of giving offset to all subframes of a corresponding
frame.
[0109] Thus, for the scanning operation coexisting with the mixed
mode, a function of a start subframe (or a subframe offset) is
turned off or interpreted differently to enable an efficient
scanning operation in case of setting mode information of a
corresponding carrier, frame offset, zone configuration information
or scan duration for the NBR_ABS.
[0110] Meanwhile, in the above described embodiments, a time for
receiving a preamble of a scan target base station substantially is
represented as a scanning interval and a time including a scanning
interval and BS switching times before and after the scanning
interval is defined as a sub-scan duration. Start frame information
indicates a frame in which a scanning interval starts in the
description of the first embodiment, while indicating a frame in
which an initial scan duration starts in the description of the
second embodiment. Thus, a name and/or meaning of a parameter
indicating a corresponding interval, a corresponding time or the
like can be changed if necessary.
[0111] Structures of Mobile Station and Base Station
[0112] In the following description, a mobile station and base
stations (FBS, MBS) according to another further embodiment of the
present invention for implementing the above described embodiments
of the present invention are explained.
[0113] First of all, a mobile station works as a transmitter in
uplink and is able to work as a receiver in downlink. A base
station works as a receiver in uplink and is able to work as a
transmitter in downlink. That is, each of the mobile station and
the base station can include a transmitter and a receiver for
transmission of information and/or data.
[0114] Each of the transmitter and the receiver can include a
processor, a module, a part and/pr a means for performing
embodiments of the present invention. In particular, each of the
transmitter and the receiver can include a module (means) for
encrypting a message, a module for interpreting the encrypted
message, an antenna for transceiving the message and the like.
Examples of these transmitting and receiving sides are explained
with reference to FIG. 6 as follows.
[0115] FIG. 6 is a block diagram for an example of a transmitting
and receiving side structure according to another embodiment of the
present invention.
[0116] Referring to FIG. 6, a left side shows a structure of a
transmitting side and a right side shows a structure of a receiving
side. The transmitting/receiving side can include an antenna 5/10,
a processor 20/30, a transmitting (Tx) module 40/50, a receiving
(Rx) module 60/70 and a memory 80/90. Each of the elements can
perform a corresponding function. The respective elements are
explained in detail as follows.
[0117] First of all, the antenna 5/10 performs a function of
transmitting a signal generated by the Tx module 40/50 externally
or a function of receiving a radio signal externally and then
delivering the received radio signal to the Rx module 60/70. If
MIMO function is supported, at least two antennas can be
provided.
[0118] The antenna, Tx module and Rx module can configure a radio
communication (RF) module.
[0119] The processor 20/30 controls overall operations of the
transmitting or receiving side in general. For instance, the
processor 20/30 can perform a controller function for performing
the above described embodiments of the present invention, a MAC
(medium access control) frame variable control function, a handover
function, an authentication function, an encryption function and
the like. In particular, the processor 20/30 can perform overall
controls to perform the handover procedures shown in FIGS. 3 to
5.
[0120] In particular, a processor of a mobile station can control a
scan request (AAI_SCN-REQ) message to be sent to a serving base
station to perform a scan operation. In doing so, information on BS
switching capability of the mobile station can be included in the
scan request message.
[0121] The processor of the mobile station can acquire information
on a scanning interval, a start frame and the like of a scan target
base station via a scan response (AAI_SCN-RSP) message received in
response to the scan request message. Accordingly, the processor is
able to control an execution of a switching to the scan target base
station at a timing point ahead of a base station shift time from a
timing point indicated by the start frame information. Afterwards,
the processor receives a preamble from the scan target base station
during the scanning interval.
[0122] Meanwhile, in case that a san duration and an interleaving
interval are included in the scan request message, the processor of
the mobile station operates in a sub-scan duration during a time
corresponding to a scanning interval and base station switching
times before and after the scanning interval and then operates in a
sub-interleaving interval until a next sub-scan duration. In this
case, the sub-scan duration can be iterated by a frame unit. The
processor can control a data exchange with a base station to be
normally performed. In this case, the start frame information can
indicate a time until a first scan duration arrives from a time of
receiving a scan response message.
[0123] Besides, the processor of the mobile station can perform
overall control operations of the operating processes disclosed in
the descriptions of the above mentioned embodiments.
[0124] The Tx module 40/50 performs prescribed coding and
modulation on data, which is scheduled to be externally transmitted
by the processor 20/30, and is then able to deliver the coded and
modulated data to the antenna 10/5.
[0125] The Rx module 60/70 reconstructs a radio signal externally
received via the antenna 5/10 into original data by performing
decoding and demodulation on the radio signal and is then able to
deliver the reconstructed original data to the processor 20/30.
[0126] A program for processing and control of the processor 20/30
can be stored in the memory 80/90. And, the memory 20/30 can
perform a function for temporary storage of inputted/outputted
data. Moreover, the memory 80/90 can include at least one storage
medium of such a type as a flash memory type, a hard disk type, a
multimedia card micro type, a card type of memory (e.g., SD memory,
XD memory, etc.), a Random Access Memory (RAM) type, an SRAM
(Static Random Access Memory type), a Read-Only Memory (ROM) type,
an EEPROM (Electrically Erasable Programmable Read-Only Memory)
type, a PROM (Programmable Read-Only Memory) type, a magnetic
memory type, a magnetic disc type, and optical disc type, and the
like.
[0127] Meanwhile, a base station uses at least one of the above
mentioned modules to perform a controller function for performing
the above-described embodiments of the present invention, an OFDMA
(orthogonal frequency division multiple access) packet scheduling,
TDD (time division duplex) packet scheduling and channel
multiplexing function, a MAC (medium access control) frame variable
control function according to a service characteristic and electric
wave environment, a fast traffic real-time control function, a
handover function, an authentication and encryption function, a
packet modulation/demodulation function for data transmission, a
fast packet channel coding function, a real-time modem control
function and the like or can further include separate means,
modules and/or parts for performing these functions.
INDUSTRIAL APPLICABILITY
[0128] Accordingly, the present invention is applicable to various
wireless access systems.
[0129] While the present invention has been described and
illustrated herein with reference to the preferred embodiments
thereof, it will be apparent to those skilled in the art that
various modifications and variations can be made therein without
departing from the spirit and scope of the invention. Thus, it is
intended that the present invention covers the modifications and
variations of this invention that come within the scope of the
appended claims and their equivalents. Moreover, claims failing to
be explicitly cited in-between are combined to construct new
embodiments or can be included as new claims by Amendment after
filing the application.
* * * * *